The iMX RT has a separate wake up controller, the GPC, that replaces
the NVIC when asleep. It adds the ability to only wake up on certain
interrupts. It seems that it requires at least one enabled interrupt
in the NVIC to turn on it's wake up circuitry. It doesn't need to
be the same interrupt as the wake up signal. For example, the RTC
in the SNVS can wake us up if a USB interrupt is enabled. Before
then it won't work. So, we enable the SNVS interrupt on start up
so it can wake us up.
The SPI flash on current Fomu firmware is slow. Circuitpython runs
XIP from SPI flash, and so execution time can also be slow. Ordinarily
this isn't a problem, however certain operations are time-sensitive.
In particular, USB function needs to be handled quickly in order to
prevent the host from re-enumerating the device.
Place several critical TinyUSB structures into RAM, as well as several
hot functions that are frequently called. This reduces execution time
at the expense of system memory, and greatly improves system stability.
Signed-off-by: Sean Cross <sean@xobs.io>
ports/atmel-samd/boards/bdmicro_vina_m0/board.c
ports/atmel-samd/boards/bdmicro_vina_m0/mpconfigboard.h
ports/atmel-samd/boards/bdmicro_vina_m0/mpconfigboard.mk
ports/atmel-samd/boards/bdmicro_vina_m0/board.c
This board includes the newly added MX25L51245G 64MB SPI flash chip
for the CircuitPython file system. Also included is the PCF2129T/2,518
high accuracy, battery backed, RTC. Also includes an independent USB
HOST connector in addition to USB DEVICE making it easy to connect USB
peripherals. Designed mainly as a general purpose module to piggy back
onto application-specific boards, it can also run low power standalone
in harsh environments for data logging and other control applications
using an appropriate enclosure.
Has been extensively tested with CircuitPython and works well.
Restructures the STM port of Circuitpython to be more generic about the STM32 chip lines to support
the F7 and H7 series of chips. Adds the new Packages directory to organize different chip layouts
between lines. Makes general changes to the Makefile to condense board-level flags to the minimum
and support the new chip series. Adds the new chip line to the Peripherals directory, along with
new python tools used to generate peripheral text automatically in the tools/ directory.
